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Reapply "[clang][bytecode] Implement __builtin_{wcscmp,wcsncmp} (#132… #132963

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Merged
merged 1 commit into from
Mar 26, 2025
Merged

Reapply "[clang][bytecode] Implement __builtin_{wcscmp,wcsncmp} (#132… #132963

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53 changes: 40 additions & 13 deletions clang/lib/AST/ByteCode/InterpBuiltin.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -212,11 +212,13 @@ static bool interp__builtin_strcmp(InterpState &S, CodePtr OpPC,
const Pointer &A = getParam<Pointer>(Frame, 0);
const Pointer &B = getParam<Pointer>(Frame, 1);

if (ID == Builtin::BIstrcmp || ID == Builtin::BIstrncmp)
if (ID == Builtin::BIstrcmp || ID == Builtin::BIstrncmp ||
ID == Builtin::BIwcscmp || ID == Builtin::BIwcsncmp)
diagnoseNonConstexprBuiltin(S, OpPC, ID);

uint64_t Limit = ~static_cast<uint64_t>(0);
if (ID == Builtin::BIstrncmp || ID == Builtin::BI__builtin_strncmp)
if (ID == Builtin::BIstrncmp || ID == Builtin::BI__builtin_strncmp ||
ID == Builtin::BIwcsncmp || ID == Builtin::BI__builtin_wcsncmp)
Limit = peekToAPSInt(S.Stk, *S.getContext().classify(Call->getArg(2)))
.getZExtValue();

Expand All @@ -231,12 +233,22 @@ static bool interp__builtin_strcmp(InterpState &S, CodePtr OpPC,
if (A.isDummy() || B.isDummy())
return false;

bool IsWide = ID == Builtin::BIwcscmp || ID == Builtin::BIwcsncmp ||
ID == Builtin::BI__builtin_wcscmp ||
ID == Builtin::BI__builtin_wcsncmp;
assert(A.getFieldDesc()->isPrimitiveArray());
assert(B.getFieldDesc()->isPrimitiveArray());

assert(getElemType(A).getTypePtr() == getElemType(B).getTypePtr());
PrimType ElemT = *S.getContext().classify(getElemType(A));

auto returnResult = [&](int V) -> bool {
pushInteger(S, V, Call->getType());
return true;
};

unsigned IndexA = A.getIndex();
unsigned IndexB = B.getIndex();
int32_t Result = 0;
uint64_t Steps = 0;
for (;; ++IndexA, ++IndexB, ++Steps) {

Expand All @@ -248,22 +260,33 @@ static bool interp__builtin_strcmp(InterpState &S, CodePtr OpPC,
!CheckRange(S, OpPC, PB, AK_Read)) {
return false;
}

if (IsWide) {
INT_TYPE_SWITCH(ElemT, {
T CA = PA.deref<T>();
T CB = PB.deref<T>();
if (CA > CB)
return returnResult(1);
else if (CA < CB)
return returnResult(-1);
else if (CA.isZero() || CB.isZero())
return returnResult(0);
});
continue;
}

uint8_t CA = PA.deref<uint8_t>();
uint8_t CB = PB.deref<uint8_t>();

if (CA > CB) {
Result = 1;
break;
} else if (CA < CB) {
Result = -1;
break;
}
if (CA > CB)
return returnResult(1);
else if (CA < CB)
return returnResult(-1);
if (CA == 0 || CB == 0)
break;
return returnResult(0);
}

pushInteger(S, Result, Call->getType());
return true;
return returnResult(0);
}

static bool interp__builtin_strlen(InterpState &S, CodePtr OpPC,
Expand Down Expand Up @@ -2120,6 +2143,10 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const Function *F,
case Builtin::BIstrcmp:
case Builtin::BI__builtin_strncmp:
case Builtin::BIstrncmp:
case Builtin::BI__builtin_wcsncmp:
case Builtin::BIwcsncmp:
case Builtin::BI__builtin_wcscmp:
case Builtin::BIwcscmp:
if (!interp__builtin_strcmp(S, OpPC, Frame, F, Call))
return false;
break;
Expand Down
46 changes: 46 additions & 0 deletions clang/test/AST/ByteCode/builtin-functions.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,8 @@ extern "C" {
extern char *strchr(const char *s, int c);
extern wchar_t *wmemchr(const wchar_t *s, wchar_t c, size_t n);
extern wchar_t *wcschr(const wchar_t *s, wchar_t c);
extern int wcscmp(const wchar_t *s1, const wchar_t *s2);
extern int wcsncmp(const wchar_t *s1, const wchar_t *s2, size_t n);
}

namespace strcmp {
Expand Down Expand Up @@ -72,6 +74,50 @@ namespace strcmp {
static_assert(__builtin_strncmp("abab\0banana", "abab\0canada", 100) == 0);
}

namespace WcsCmp {
constexpr wchar_t kFoobar[6] = {L'f',L'o',L'o',L'b',L'a',L'r'};
constexpr wchar_t kFoobazfoobar[12] = {L'f',L'o',L'o',L'b',L'a',L'z',L'f',L'o',L'o',L'b',L'a',L'r'};

static_assert(__builtin_wcscmp(L"abab", L"abab") == 0);
static_assert(__builtin_wcscmp(L"abab", L"abba") == -1);
static_assert(__builtin_wcscmp(L"abab", L"abaa") == 1);
static_assert(__builtin_wcscmp(L"ababa", L"abab") == 1);
static_assert(__builtin_wcscmp(L"abab", L"ababa") == -1);
static_assert(__builtin_wcscmp(L"abab\0banana", L"abab") == 0);
static_assert(__builtin_wcscmp(L"abab", L"abab\0banana") == 0);
static_assert(__builtin_wcscmp(L"abab\0banana", L"abab\0canada") == 0);
#if __WCHAR_WIDTH__ == 32
static_assert(__builtin_wcscmp(L"a\x83838383", L"a") == (wchar_t)-1U >> 31);
#endif
static_assert(__builtin_wcscmp(0, L"abab") == 0); // both-error {{not an integral constant}} \
// both-note {{dereferenced null}}
static_assert(__builtin_wcscmp(L"abab", 0) == 0); // both-error {{not an integral constant}} \
// both-note {{dereferenced null}}

static_assert(__builtin_wcscmp(kFoobar, kFoobazfoobar) == -1);
static_assert(__builtin_wcscmp(kFoobar, kFoobazfoobar + 6) == 0); // both-error {{not an integral constant}} \
// both-note {{dereferenced one-past-the-end}}

static_assert(__builtin_wcsncmp(L"abaa", L"abba", 5) == -1);
static_assert(__builtin_wcsncmp(L"abaa", L"abba", 4) == -1);
static_assert(__builtin_wcsncmp(L"abaa", L"abba", 3) == -1);
static_assert(__builtin_wcsncmp(L"abaa", L"abba", 2) == 0);
static_assert(__builtin_wcsncmp(L"abaa", L"abba", 1) == 0);
static_assert(__builtin_wcsncmp(L"abaa", L"abba", 0) == 0);
static_assert(__builtin_wcsncmp(0, 0, 0) == 0);
static_assert(__builtin_wcsncmp(L"abab\0banana", L"abab\0canada", 100) == 0);
#if __WCHAR_WIDTH__ == 32
static_assert(__builtin_wcsncmp(L"a\x83838383", L"aa", 2) ==
(wchar_t)-1U >> 31);
#endif

static_assert(__builtin_wcsncmp(kFoobar, kFoobazfoobar, 6) == -1);
static_assert(__builtin_wcsncmp(kFoobar, kFoobazfoobar, 7) == -1);
static_assert(__builtin_wcsncmp(kFoobar, kFoobazfoobar + 6, 6) == 0);
static_assert(__builtin_wcsncmp(kFoobar, kFoobazfoobar + 6, 7) == 0); // both-error {{not an integral constant}} \
// both-note {{dereferenced one-past-the-end}}
}

/// Copied from constant-expression-cxx11.cpp
namespace strlen {
constexpr const char *a = "foo\0quux";
Expand Down